The present invention relates to pipe repair. Specifically, the present invention relates to a new method and device for lining pipe.
A system which is commonly used for repairing damaged sewer pipes is called cured-in-place pipe repair. Cured-in-place pipe repair is typically a fabric felt-type liner, impregnated with a liquid resin, formed inside an existing conduit or pipe and cured or hardened to become a one-piece continuous new pipe lining. The liner is pressed outward against the pipe using an expandable bladder. The resin cures, forming the liner tightly along the inside of the pipe in the damaged area, thereby creating a water tight seal and repairing the pipe.
Cured-in-place technology is used to renew main sewer pipes, lateral sewer pipes as well as other types of conduits. When using cured-in-place pipe repair for renewing both main and lateral pipes, the lining is generally either pulled in place and inflated or inverted into place and inflated. One problem, however, with this type of pipe repair is that the edges of the liner create ridges inside the pipe where solids can collect and create blockage inside the pipe. This is particularly problematic on the edge at the upstream end of the liner.
In general, when a section of cured-in-place pipe, whether straight, curved, or pipe junction, is placed in a sewer pipe, the edge of the liner is raised by the thickness of the liner and thus creates an area for buildup of solids, thereby blocking the pipe. Thus, it is desirable to have an improvement in cure-in-place pipe liners.
When these liners are pulled into place or inverted into place the liner is generally attached to the bladder in some manner to get the liner into proper position inside the damaged pipe. Then, once the resin cures, the bladder is removed. However, to remove the bladder, the connection between the bladder and the liner must be frangible. Therefore, connections between the bladder and the liner have used connecting strips stitched to the bladder and held to the liner with an adhesive or other means which can be broken. Stitching the fabric liner directly to the bladder puts unwanted holes in the liner which may leak at the damaged portion of the pipe once the stitches are removed or broken and dissolved. Another problem with these and other known frangible connections between the bladder and the liner is that the frangible connection is difficult to break once the liner resin cures in place inside the pipe. Therefore an improved frangible connection between the bladder and the liner is desirable.
In light of the foregoing, the primary feature and advantage of the present invention is to provide an improved new method and device for lining pipe.
A further feature or advantage of the present invention is a device for lining pipe which reduces solids accumulation and thus reduces chance for blockage of pipe repairs.
A further feature or advantage of the present invention is a method of lining pipe which reduces blockage in the pipe being repaired.
Another feature or advantage of the present invention is a method of frangibly connecting a liner tube to an elongated positioning tube or an inversion bladder where the frangible attachment is strong during placement of the liner, yet can be easily broken or separated during removal of the positioning tube or bladder once the liner resin has cured.
Yet another feature or advantage of the present invention is a device for frangibly connecting a pipe repair liner to an expansion bladder which is strong during placement of the liner yet can be easily broken or disconnected during removal of the positioning hose or bladder once the liner resin has cured.
A further feature or advantage of the present invention is a device for lining pipe which is economical to manufacture, durable in use and efficient in operation.
One or more of these and/or other features or advantages of the present invention will be apparent from the specification and claims that follow.